Anode structure



United States Patent "ice 3,154,714 ANODE STRUCTURE Lewis R. Gormay, Normandy Beach, N.J., assignor to Radio Corporation of America, a corporation of Delaware Filed May 29, 1961, Bar. No. 113,382 9 Claims. (Cl. 313356) This invention relates to electron discharge tubes of the beam power type, and particularly to an improved and novel anode electrode for such tubes.

In certain types of electron tubes known as beam power tubes having aligned control and screen grids and beam defining electrodes, a problem associated with the use of such tubes is spurious oscillations. For example, when using beam power tubes in the horizontal deflection circuitry of television receivers, spurious oscillations emanating from the beam power tubes are radiated, picked up by the antenna or circuit components adjacent the tube, and transmitted through the receiver givlng rise to jagged vertical lines on the picture tube known as snivets.

As known, one means for preventing such oscillations is to provide a flange or fin extending inwardly from the active or electron-receiving portions of the anode towards the cathode and into the stream of electrons. However, because of the large amount of heat produced at the anodes of power tubes by the kinetic energy of the electrons striking the anodes, it is desirable to provide heat dissipating flanges adjacent the active portions of the anodes. These flanges, however, must extend outwardly away from the cathode and towards the tube envelope in order to permit dissipation of the heat by radiation. Heretofore, it was not known how to provide anode electrodes having both integral outwardly extending, heat dissipating flanges and integral, inwardly extending snivet fins. In order to pro vide both the outwardly extending heat dissipating flanges and the inwardly extending snivet fins, it has been the practice to form the anodes with integral heat dissipating flanges and to add separate snivet fins thereto during mount assembly. Such practice is undesirable since it adds extra cost to the tube.

Therefore, it is an object of this invention to provide an improved and novel anode electrode structure for preventing spurious oscillations in beam power tubes.

Particularly, it is an object of this invention to provide an improved and novel anode electrode structure for preventing spurious oscillations within beam power tubes wherein separate snivet fin inserts are not required and wherein both inwardly and outwardly extending integral flanges at the active portions of the anode are provided. Fonachieving these and other objects according to this invention, an anode electrode is provided which cornpnses a pair of plates of substantially U-shaped cross section, each plate having laterally extending flanges at the open end of the U. Within an electron tube using the anode, the two plates are arranged to surround the other tube electrodes, the plates being joined at their flanges. The inner sides of the Us provide the active areas of the anode and the joined flanges serve as a pair of outwardly extending, heat dissipating radiators. {For providing the inwardly extending snivet fins, a flan 1s Sllt in each of the flanges, one flap from each pair of joined flanges being turned to extend inwardly to wards the other tube electrodes. The remaining two flaps are bent out of the plane of the flanges to extend through the openings in the flanges left by the first two flaps for reasons to be described hereinafter.

In the drawings:

FIG. 1 is an elevational view, partly broken awa, of

3,154,?14 Patented Oct. 27, 1964 a beam power tube of the type wherein the anode of this invention may be utilized;

FIG. 2 is a view in perspective showing the anode halves or plates according to this invention in assembled form; and

FIG. 3 is an exploded view of the anode assembly shown in FIG. 2.

The electron tube 10 shown in FIG. 1 includes a cage comprising a pair of insulating mica spacers 11 and 12 between which is held in properly spaced relationship a cathode 14 of the indirectly heated type, a pair of grids in aligned relationship so that only the lateral wire turns 16 of the screen grid 18 are visible, the control grid 20 and the screen grid 13 having side rods 22 and 24, respectively, a beam confining plate 26, and the two halves or plates 28 and 31 of the anode electrode 35 of this invention. A heater is included for heating the cathode 1 only the bottom leads 32 thereof being visible. Also shown is a stem 37 having a number of support and lead-in conductors 38 welded to the lower ends of the tube electrodes for providing support to the cage and electrical connections with the tube electrodes.

The anode electrode 35 made according to this invention is shown in greater detail in F163. 2 and 3. The anode comprises a pair of plates 28 and 39. Each plate is of generally U-shape and is provided with a pair of extending flanges 4i) and 42. For securing the plates 28 and 33 together, as shown in FIG. 3, tongues 44 may be provided on the flanges 40 with corresponding openings 45 provided in flanges 42. When the plates are assembled tongues 44 extend through the openings 45 and are bent over for clamping the plates together. Each pair of joined flanges 4i) and 42 serve as an outwardly extending heat radiator. The active portions of the anode 35 which receive the electron stream from the cathode 14 are the inside surfaces 47 of side portions 48. Side portions 4-8 along with end portions 4? provide a tubular structure which surrounds the other tube electrodes as shown in FIG. 1.

For providing the snivet fins used to prevent spurious oscillations, the flanges 40 are slit to provide elongated, rectangular flaps 52 having three free edges. The fourth edge of the flaps 52 is substantially coincident with the line at which the flanges 42 join the side portions 48 of the plate 28. As shown, flaps 52 on plate 28 are bent through an angle of 180 so as to extend inwardly of the anode in the plane of the flanges 42. Flaps 52 thus serve as snivet fins when the assembled anode is incorporated Within a tube 10.

As shown in FIG. 3, apertures 56 are provided in flanges 4d of plate 23 upon bending of flaps 52. Although these apertures 56 are in the plane of the flanges which are parallel to the path of the electrons flowing from the cathode to the anode,'it has been found that some electrons streaming past flaps 52 find their way through apertures 56 and thence against the tube envelope. In those instances wherein the envelopes are of glass, such bombardment, as known, results in the breakdown of the glass and the eventual destruction of the tube.

For closing apertures 56 and preventing such envelope bombardment flaps 54 similar to flaps 52 are rovided in flanges 42 of plate 39 and from the plane of flanges 42 are bent so as to form extensions of side portions 48 of plate 3%. When plates 28 and 39 are assembled, as shown in FIG. 2 flaps 54 extend through apertures 56 and along the outside of side portions 48 of plate 28, thereby presenting a continuous and closed active anode area towards the cathode.

It has been found, for reasons not fully known, that best suppression of spurious oscillations occurs when the snivet fins are located in the plane of the flanges, that is, in the region of densest electron flow, and when the snivet snee /1s 3 fins comprise flat, thin plates extending parallel to the electron stream and perpendicular to the anode active area.

In one embodiment of this invention wherein the distance between mica spacers 11 and 12 is 1.250 inch, the electron emitting'portion of the cathode 14 is 985 mils in length, the distance between the lateral wire turns 16 of the screen grid 18 and the active area of the anode 35 in the plane of the flanges 4t? and 42 is 115 mils, the length of flaps 52 is 0() mils, the width of the flaps 52 is 58 mils, and the thickness of the flaps is 19 mils.

In the fabrication of the tube shown in FIG. 1 all the tube electrodes including plate 28 but excluding plate 36 are assembled between the mica spacers 11 and 12, apertures being provided in the spacers for receiving end portions of the electrodes such as ears 58 of plate 28. The assembled cage is then mounted on the stem 37, two leads 3% extending upwardly through the cage and being welded to the beam plate 26 for providing a rigid mount assembly. Thereafter the lateral wire turns of the control grid Zfl and the screen grid 18 are aligned and the grids fixed from relative movement by welding the grid side rods 22 and 24- to leads 38.

Having assembled the mount, the remaining plate 30 is secured to plate 28 as described to complete the anode electrode 35, the anode surrounding the other tube electrodes. A glass bulb 6t) is shelled onto the mount, and the tube then exhausted and sealed in any suitable manner. The electrical connection with the anode 35 may be made through a lead 62 extending upwardly through the top end of the envelope 6% and vacuum sealed thereto.

What is claimed is:

1. In an electron discharge tube comprising a plurality of electrodes, a tubular anode comprising two plates, one of said plates having a flange extending outwardly of said anode and being slit to provide a flap therein, said flap being turned to extend inwardly of said anode, thereby leaving an opening in said flange, and a portion of the other of said plates extending through said opening.

2. In an electron discharge tube comprising a plurality of electrodes, an anode comprising a pair of plates forming a tubular structure, each plate having a flange extending outwardly from said structure, a first flap slit from one of said flanges and turned therefrom to extend in-- wardly of said structure, thereby providing an opening in said flange, a second flap slit in the other of said flanges and extending through the opening in said one flange.

3. In an electron discharge device comprising a plurality of electrodes, an anode comprising a tubular structure, having a pair of adjacent flanges extending outwardly from opposing sides thereof, said flanges having flap portions cut therein, one of said flaps from each of said pair of flanges being arranged so as to extend inwardly of said structure, the remaining of said flaps being arranged to extend through the apertures in said flanges provided by said inwardly extending flaps.

4. in an electron discharge device comprising a plurality of elongated electrodes and a pair of oppositely disposed spacer plates mounted on the ends of said electrodes for providing relative spacing of said electrodes, said electrodes including a pair of wound grids having aligned lateral wire turns, an anode comprising a tubular structure having a pair of adjacent flanges extending outwardly from opposing sides thereof, said flanges having flap portions cut therein, one of said flaps from each of said pair of flanges being turned from said flanges so as to extend inwardly of said structure, the remaining of said flaps being turned perpendicularly to said flanges and arranged to extend through the apertures in said flanges left by said inwardly extending flaps.

5. In an electron discharge device comprising a plurality of elongated electrodes, an anode comprising two sections of substantially U-shaped cross section, each section having a pair of laterally extending flanges, said sections being joined at said flanges to form a tubular structure with said flanges extending outwardly therefrom, longitudinally extending flaps slit in said flanges and turned away therefrom providing elongated apertures in said flanges, said flaps of one of said sections extending inwardly of said structure, and said flaps of the other of said sections extending through said apertures of said one section and on the outside of said structure.

6. In an electron discharge device comprising a plurality of elongated electrodes including a cathode, control and screen grids having aligned lateral wire turns, and a beam confining plate, an anode including two plates of substantially U-shaped cross section, each plate having laterally extending flanges at the open end of the U, said plates. being joined at said flanges and forming a tubular structure, said flanges being slit to provide elongated rectangular flaps therein, the side of said flaps joined to said flanges being substantially coincident with the open end of said U, said flaps of one of said plates extending inwardly of said structure, and said flaps of 'the other of said plates extending through the apertures left by said inwardly extending flaps and along the side walls of said one plate.

7. In an electron discharge device comprising a plurality of electrodes, a tubular anode, said anode being slit to provide a flap extending inwardly of said anode, thereby leaving an opening in said anode, and means for sub-' stantially closing said opening.

8. In an electron discharge device comprising a plurality of electrodes, a tubular anode having a flange extending outwardly therefrom, said flange being slit to provide a flap extending inwardly of said anode, thereby leaving an opening in said flange, and means for substantially closing said opening. I

9. In an electron discharge device comprising a plurality of electrodes, a tubular anode having an outwardly extending flange, said flange being slit to provide an inwardly extending flap, thereby leaving an opening in said flange, and a portion of said anode extending through said opening for substantially closing said opening.

References Cited in the file of this patent UNITED STATES PATENTS 2,158,996 Zitzler May 23, 1939 2,451,328 Foulkes Oct. 12, 1948 2,843,787 Rinn July 15, 1958 

1. IN AN ELECTRON DISCHARGE TUBE COMPRISING A PLURALITY OF ELECTRODES, A TUBULAR ANODE COMPRISING TWO PLATES, ONE OF SAID PLATES HAVING A FLANGE EXTENDING OUTWARDLY OF SAID ANODE AND BEING SLIT TO PROVIDE A FLAP THEREIN, SAID FLAP BEING TURNED TO EXTEND INWARDLY OF SAID ANODE, THEREBY LEAVING AN OPENING IN SAID FLANGE, AND A PORTION OF THE OTHER OF SAID PLATES EXTENDING THROUGH SAID OPENING. 